Adela Chacón was 27 when she said goodbye to her three children in Escuíntla, in southwestern Guatemala, and left for work. When she didn’t return, her sisters went looking for her. The next day she was found dead in an empty ditch, beaten beyond recognition.

Described as a David-versus-Goliath story, “Justicia para mi hermana” (“Justice for my Sister”) is the debut feature-length documentary from Kimberly Bautista that tracks a woman’s heroic journey to prosecute the man who murdered her sister.

Having recently been crowned Best Long-Form Central American documentary at the Ícaro Film Festival in Guatemala, “Justice for my Sister” had its Costa Rican premiere in San José on Wednesday evening, sponsored by the embassies of Canada and the Netherlands.

Filmed over three years, the documentary shines a light on Guatemala’s femicide epidemic and highlights the country’s machismo culture.

In the last decade more than 6,000 women have been murdered in the Central American country and only 2 percent of their killers have been sentenced. According to a 2012 report by the Small Arms Survey, Guatemala has the third highest rate of femicide in the world.

In 2008, the government passed a law that defined femicide as a specific crime against women, carrying a prison sentence of 25 to 50 years, without parole. A special prosecutor, police units and tribunals were set up to deal exclusively with the gender-related crime, but so far Guatemala’s high femicide rates show little signs of abating.

Adela was just another number to law enforcement agencies until her sister Rebeca refused to give up hope of seeing the killer held to account. “Justice for my sister” follows Rebeca as she takes on Guatemala’s notoriously weak justice system and uses her traumatic loss for personal growth, emerging as a feminist leader in her community.

Los Angeles, California-based filmmaker Bautista, a Colombian and Irish-American, first met Rebeca during a trip to Guatemala where she worked with women’s organizations.

“We clicked immediately,” says Bautista. “She had a lightness to her spirit, despite her heavy situation. And her dedication to see the trial through to a sufficient sentencing made her that much more relatable to a wider audience in my eyes.”

During her three-year battle, Rebeca encounters various setbacks: a missing police report, a judge accused of killing his own wife, and witnesses who are too afraid to testify. Adela’s 13-year-old daughter even became the target of a drive-by shooting aimed at stopping her from identifying an ex-boyfriend as the man who harassed and threatened her mother.

Despite the setbacks, Rebeca continued to juggle the case around her job, making tortillas for nine hours each day, and taking care of her five children – as well as the three her sister left behind.

From its initial inception as a proposed project on a graduate school application, “Justice For My Sister” has now won various awards including Best Documentary at the Latino International Film Festival in Los Angeles and Best Foreign Film at the International Film Festival in Nevada.

“In the case of a documentary that deals with human rights issues, getting an audience to see a film can be a question of life or death. I ultimately hope to affect real change in people’s lives by educating audiences about these unsolved and sometimes unreported murders,” says Bautista. “I hope that audiences will be inspired by Rebeca’s unwavering determination to bring justice to light and will question how they can contribute to diminish violence against women and rework the way they think about gender power dynamics in their own lives.”

Says Bautista: “I believe that speaking out is essential in order to encourage audiences to break the silence and to challenge the stigma that marks sexual violence.”